HONOLULU (AP) — A Hawaii Air National Guard civilian contractor was in serious condition Wednesday after his plane crashed off the coast of Honolulu during a military exercise, authorities said.

The pilot of the Hawker Hunter jet ejected safely from the plane, Joint Base Pearl Harbor-Hickam said in a statement. He was initially rescued by a private sailboat and then transferred to the U.S. Coast Guard.

Honolulu Emergency Services spokesman Dustin Malama said the 47-year-old appeared to have traumatic injuries and was taken to a hospital.

Federal Aviation Administration spokesman Ian Gregor said a Hawker Hunter jet went down in the ocean around 2:25 p.m. after taking off from Honolulu’s airport.

The pilot was rescued about 3 miles (4.8 kilometers) south of Oahu near Honolulu’s Sand Island, the U.S. Coast Guard said.

The pilot had been participating in a military exercise called Sentry Aloha, which was temporarily suspended after the crash. The exercise will resume Thursday morning.

The Hawaii Air National Guard was hosting the exercise, which involved about 800 personnel and 30 aircraft from nine states.

The cause of the crash was under investigation, the military said.

Departing flights from the Honolulu airport were held as a precaution for about 20 minutes, said Tim Sakahara, spokesman for the state Department of Transportation.

The Hawker Hunter is a British jet developed in the late 1940s and early 1950s, said the website of defense contractor BAE Systems.

Initially, a single-seat version was used as a maneuverable fighter aircraft. It was later used as both a fighter and bomber and for reconnaissance missions.

The British navy and air force continued to use a two-seat version into the early 1990s.

Britain exported the plane, and it was also used by the air forces of 21 other nations.